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Author Thiede, V. M. T. ♦ Jeitschko, W.
Sponsorship Deutsche Forschungsgemeinschaft, Bonn (Germany)
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword MATERIALS SCIENCE ♦ CRYSTAL STRUCTURE ♦ CHEMICAL PREPARATION ♦ LANTHANUM ALLOYS ♦ MOLYBDENUM ALLOYS ♦ ALUMINIUM ALLOYS ♦ TUNGSTEN ALLOYS ♦ LATTICE PARAMETERS ♦ BOND LENGTHS ♦ EXPERIMENTAL DATA
Abstract The title compounds have been prepared by reaction of the elemental components in alumina crucibles. Their crystal structure was determined from single-crystal X-ray data of La{sub 4}Mo{sub 7}Al{sub 51}: P{bar 3}m1, a = 1042.4(3) pm, c = 1174.3(3) pm, Z = 1, R = 0.023 for 892 structure factors and 62 variables. The lattice constants of the isotypic compound La{sub 4}W{sub 7}Al{sub 51} are a = 1041.3(4) pm, c = 1173.3(4) pm. The structure is closely related to that reported for Ca{sub 4}Cr{sub 7}Al{sub 48}. The atoms occupy 12 atomic positions, of which four show significant deviations from the full occupancy, resulting in the formula La{sub 3.662(4)}Mo{sub 7}Al{sub 50.26(8)}. All atoms have high coordination numbers. The two different lanthanum atoms are coordinated by 1 lanthanum and 15 aluminum atoms, the two molybdenum sites by 12 and 11 aluminum atoms, respectively, in the form of bi and monocapped pentagonal antiprisms. The eight different aluminum atoms have between 11 and 14 neighbors with between 2 and 4 lanthanum and/or molybdenum atoms. All coordination polyhedra of the aluminum atoms have at least some rectangular or nearly rectangular faces.
ISSN 00224596
Educational Use Research
Learning Resource Type Article
Publisher Date 1999-03-01
Publisher Place United States
Journal Journal of Solid State Chemistry
Volume Number 143
Issue Number 2


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